Having lived in the south of the caribbean for a number of years now, ive seen kite charters come and go through St Lucia, and have joined on a few myself.
In my opinion there is one kite charter that stands out way above the rest.
Ben Findlay on the yacht 'Carla' his website is www.caribbeankitesurfari.com
Contact him on firstname.lastname@example.org
He knows these waters for kitesurfing amd surfing better than anyone around, and being a waterman himself will take you to a spot to ride whatever conditions you are looking for. The area of St Lucia to the Grenadines is amazing sailing and kiting, and still uncrowded with plenty of spots to ride in and such friendly locals with a chilled caribbean vibe.
Ben is also a family man, so knows how to kep everyone entertained the whole time and maximise time on the water. Oh, did i mention he makes a pretty sweet rum punch at sunset
This is not shameless pimpin, just my honest opinion!
Enjoy da caribbean mon